title: miR-30a regulates endothelial tip cell formation and arteriolar branching.
abstract: Microvascular rarefaction increases vascular resistance and pressure in systemic arteries and is a hallmark of fixed essential hypertension. Preventing rarefaction by activation of angiogenic processes could lower blood pressure. Endothelial tip cells in angiogenic sprouts direct branching of microvascular networks; the process is regulated by microRNAs, particularly the miR-30 family. We investigated the contribution of miR-30 family members in arteriolar branching morphogenesis via delta-like 4 (Dll4)-Notch signaling in a zebrafish model. The miR-30 family consists of 5 members (miR-30a-e). Loss-of-function experiments showed that only miR-30a reduced growth of intersegmental arterioles involving impaired tip cell function. Overexpression of miR-30a stimulated tip cell behavior resulting in augmented branching of intersegmental arterioles. In vitro and in vivo reporter assays showed that miR-30a directly targets the Notch ligand Dll4, a key inhibitor of tip cell formation. Coadministration of a Dll4 targeting morpholino in miR-30a morphants rescued the branching defects. Conversely, conditional overexpression of Notch intracellular domain restored arteriolar branching in miR-30a gain-of-function embryos. In human endothelial cells, loss of miR-30a increased DLL4 protein levels, activated Notch signaling as indicated in Notch reporter assays, and augmented Notch downstream effector, HEY2 and EFNB2 (ephrin-B2), expression. In spheroid assays, miR-30a loss- and gain-of-function affected tip cell behavior, consistent with miR-30a targeting Dll4. Our data suggest that miR-30a stimulates arteriolar branching by downregulating endothelial Dll4 expression, thereby controlling endothelial tip cell behavior. These findings could have relevance to the rarefaction process and, therefore, to hypertension.
authors.affiliation: Department of Angiogenesis and Cardiovascular Pathology, Max Delbrück Center for Molecular Medicine, Robert Roessle Strasse 10, D13125 Berlin, Germany.
authors.forename: Qiu
authors.initials: Q
authors.lastname: Jiang
authors.forename: Mariana
authors.initials: M
authors.lastname: Lagos-Quintana
authors.forename: Dong
authors.initials: D
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Shi
authors.forename: Christian
authors.initials: C
authors.lastname: Helker
authors.forename: Wiebke
authors.initials: W
authors.lastname: Herzog
authors.forename: Ferdinand
authors.initials: F
authors.lastname: le Noble
mesh_terms: D000818:Animals; D001160:Arterioles / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D002450:Cell Communication / Q000502:physiology; D048430:Cell Shape / Q000502:physiology*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D036388:Ephrin-B2 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D051880:Receptors, Notch / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D015027:Zebrafish
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D036388:Ephrin-B2; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D035683:MicroRNAs; D051880:Receptors, Notch; D012097:Repressor Proteins; C405693:HEY2 protein, human; C546086:MIRN30b microRNA, human; C064045:delta protein
keywords: Notch receptors; angiogenesis; microRNAs